Risk factor analysis for aortic dissection after aortic valve replacement in patients with tricuspid aortic valve

OBJECTIVE

Aortic dilatation concurrent with aortic valve disease is a common condition. However, the incidence of aortic dissection after aortic valve replacement for tricuspid aortic valve has not been fully investigated. Therefore, we performed a risk factor analysis for the incidence of aortic dissection after aortic valve replacement in patients with tricuspid aortic valve.

METHODS

We retrospectively reviewed 599 patients who underwent aortic valve replacement at our hospital between January 2000 and December 2020. We performed a risk factor analysis for the incidence of aortic dissection after aortic valve replacement in patients with tricuspid aortic valve.

RESULTS

Seven patients developed late aortic dissections during the follow-up period. All patients with aortic dissection underwent aortic valve replacement for aortic regurgitation. Multivariable analysis revealed that aortic regurgitation was an independent predictor of aortic dissection (p < 0.0001). The mean ascending aortic diameter at aortic valve replacement for aortic regurgitation was significantly greater in patients with aortic dissection than in those without aortic dissection (46 [43.5-46] mm vs. 39 [36-42] mm, p < 0.001). The predictive cutoff value of ascending aortic diameter was indicated using receiver operating characteristic curve analysis; 46.0 mm (area under the curve: 0.8987). Freedom rates from aortic dissection in patients with aortic regurgitation and an ascending aortic diameter ≥ 46 mm were significantly lower than those in patients with an ascending aortic diameter < 46 mm (66.7% vs. 100% at 5 years, p < 0.0001).

CONCLUSION

Aortic regurgitation combined with ascending aortic dilatation at aortic valve replacement could be a significant risk factor for late aortic dissection.

Configuration of the neoaortic root after chimney reconstruction in the Norwood procedure

OBJECTIVES

After staged reconstruction for hypoplastic left heart syndrome, the neoaortic root tends to dilate, and the incidence of significant neoaortic valve insufficiency increases with time. This study aimed to evaluate the mid-term outcomes of the neoaortic root geometries and valve function after chimney reconstruction in the Norwood procedure.

METHODS

Between 2013 and 2021, 20 consecutive patients who underwent chimney reconstruction during the Norwood procedure for hypoplastic left heart syndrome and its variants in our institution were enrolled. The actual diameters of the following points were measured, and Z-scores were calculated based on the normal aortic root geometries using the long axis view of echocardiography at the pre-Norwood stage and the lateral view of angiography at pre-Glenn, pre-Fontan, post-Fontan and follow-up (age 5-6 years) stages: neoaortic valve annulus; sinus of Valsalva; sinotubular junction; and ascending aorta just proximal to the anastomosis to the aortic arch. The degree of neoaortic valve regurgitation was evaluated by echocardiography at each stage.

RESULTS

The median follow-up period was 3.9 years. Neoaortic roots after chimney reconstruction were spared from progressive dilation over time. With growth, the conical configuration of the neoaortic roots was preserved without geometrical distortion. The Z-scores of the annulus, sinus of Valsalva, sinotubular junction and ascending aorta ranged roughly from 4 to 6, 4 to 6, 2 to 4 and 0 to 2, respectively. All neoaortic valves at each stage had mild or no regurgitation.

CONCLUSIONS

Chimney reconstruction prevented neoaortic root dilation and avoided significant neoaortic valve regurgitation in the mid-term. These neoaortic dimensions with smooth flow profiles in the neoaorta after chimney reconstruction may have contributed to the current results. Further studies are needed to clarify the long-term outcomes.

Impact of Intensive Low-Density Lipoprotein Cholesterol-Lowering Therapy on Coronary Artery Plaques in Acute Coronary Syndrome

Acute coronary syndrome (ACS) is associated with a high incidence of unstable plaques beyond the culprit lesion, leading to early recurrence of cardiovascular events. Coronary computed tomography angiography (CCTA) can be used to noninvasively observe plaques throughout the coronary arteries. To evaluate the impact of intensive low-density lipoprotein cholesterol (LDL-C)-lowering therapy on quantitative changes in coronary plaque, assessed using CCTA in a study population with ACS. In total, 81 consecutive patients with ACS who underwent CCTA at discharge and at 1-year follow-up from April 2018 to March 2020 were analyzed. The patients were divided into 2 groups: those who achieved LDL-C <70 mg/100 ml and those who did not. Changes in plaque morphology within and between the 2 groups were compared using CCTA. A total of 198 vessels were analyzed. The calcified plaque volume was significantly increased in the LDL-C <70 group (65.8 ± 80.1 mm3 to 73.6 ± 83.7 mm3, p = 0.007), whereas no significant change was observed in the LDL-C ≥70 group (106.9 ± 161.7 mm3 to 105.7 ± 137.5 mm3, p = 0.552). Percent change in low-attenuation plaque volume in the LDL <70 group was significantly lower than in the LDL-C ≥70 group (17.2 ± 90.9% vs 84.4 ± 162.6%, p = 0.020). Receiver operating characteristic curve analysis demonstrated that the target LDL-C level for low-attenuation plaque volume regression was 64 mg/100 ml. In conclusion, noninvasive CCTA demonstrated that intensive LDL-C lowering in high-risk patients with ACS could potentially lead to plaque stabilization.

A new predictor of the optimal pulmonary artery reconstruction method during the arterial switch operation

OBJECTIVES

The aim of this study was to more accurately predict the optimal pulmonary artery (PA) reconstruction procedure (Lecompte manoeuvre or original Jatene procedure) during the arterial switch operation, we focused on the horizontal sectioning (HS) angle between the left hilum PA and the great arteries using preoperative computed tomography imaging.

METHODS

We defined the HS angle α (β) as the angle between the tangential line from the posterior (anterior) wall of the left PA at the hilum to the left anterior (right posterior) surface of the main PA and the tangential line from the left surface of the ascending aorta to the left anterior (right posterior) surface of the main PA. We identified 14 consecutive patients diagnosed with transposition of the great arteries or transposition of the great artery-type double-outlet right ventricle who underwent preoperative computed tomography imaging. The original Jatene or Lecompte procedure was used for 9 (OJ group) and 5 (L group) patients. Relationships of the great arteries of the OJ and L groups were side by side in 8 and 2 patients, oblique in 1 and 1 patient and anteroposterior in 0 and 2 patients, respectively.

RESULTS

In the OJ group, β was greater than α in all patients. The median α/β value was 0.618. In group L, α was greater than β in all patients. The median α/β was 1.307. Left PA stenosis caused by stretching was not observed in the L group. Coronary obstruction was not identified in the OJ group. Left PA stenosis behind the neo-ascending aorta was observed in 1 patient in the OJ group and required reoperation.

CONCLUSIONS

The HS angle may be a useful predictor of optimal intraoperative PA reconstruction during arterial switch operation, especially for side-by-side or oblique relationships.

Angiographic Coronary Calcification: A Simple Predictor of Long-Term Clinical Outcomes in Patients with Acute Myocardial Infarction

AIMS

Coronary calcification detected by coronary angiography is a simple risk marker for long-term clinical outcomes in stable coronary artery disease. However, the significance of angiographic coronary calcification in the culprit lesion of acute myocardial infarction (AMI) has not been fully discussed. The purpose of this retrospective study was to assess the usefulness of angiographic coronary calcification as a risk marker for long-term clinical outcomes following percutaneous coronary intervention to the culprit lesions of AMI.

METHODS

We included 1209 patients with AMI and divided them into the none-mild calcification group (n=923) and the moderate-severe calcification group (n=286) according to angiographic coronary calcification in the culprit lesion of AMI. The primary endpoint was the occurrence of major adverse cardiac events (MACE), which was defined as a composite of all-cause death, nonfatal MI, readmission for heart failure, and ischemia-driven target vessel revascularization.

RESULTS

The median follow-up duration was 542 (Q1: 182, Q3: 990) days. A total of 345 MACE were observed during the study period. The occurrence of MACE was significantly greater in the moderate-severe calcification group than in the none-mild calcification group (43.4% vs. 23.9%, p＜0.001). In the multivariate Cox hazard model, moderate-severe calcification was significantly associated with MACE (hazard ratio 1.302, 95% confidence interval 1.011-1.677, p=0.041) after controlling multiple confounding factors.

CONCLUSIONS

Angiographically moderate to severe calcification in AMI culprit lesion was associated with long-term worse clinical outcomes. Angiographic coronary calcification can be a simple risk marker in patients after AMI.

Giant coronary pseudoaneurysm associated with stent fracture treated successfully with coil embolization and a vascular plug

A 59-year-old man with acute cholangitis was referred to us because of a coronary artery aneurysm that was incidentally detected on contrast-enhanced computed tomography. Intravascular ultrasonography showed a loss of vascular layers and complete stent fracture, which was suggestive of a pseudoaneurysm. After some management protocols, such as observation, covered stent implantation, and surgical treatment, had failed, we treated the pseudoaneurysm successfully using coil embolization and a vascular plug. There were no complications during the perioperative period. We suggest that, if conventional management fails, treatment with coil embolization and a vascular plug should be considered.

Learning objective

A rare complication of percutaneous coronary intervention resulting from stent fracture is a coronary artery aneurysm. Here, we discuss the chronic complications of stent implantation and discuss the optimal management strategy for coronary pseudoaneurysms. Further, we discuss the strengths and weaknesses of each strategy.

Multiple Pulmonary Artery Plasty With Tissue-Engineered Vascular Grafts

In pediatric cardiovascular surgery, the autologous pericardium is useful for pulmonary artery augmentation. However, in some cases, the autologous pericardium may not be available for various reasons. Since 2014, we have developed tissue-engineered vascular grafts (TEVGs) and obtained good results. We report a successful case of multiple pulmonary artery plasty with TEVGs for pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries. TEVGs are useful alternatives to autologous pericardium in pediatric cardiovascular operations that often require multistage procedures.

Association of collateral flow with clinical outcomes in patients with acute myocardial infarction

Coronary collateral flow is an important prognostic marker in percutaneous coronary intervention (PCI) for chronic total occlusion. However, the role of collateral flow to the culprit lesion of acute myocardial infarction (AMI) has not been fully established yet. The purpose of this retrospective study was to examine the association between collateral flow and long-term clinical outcomes in patients with AMI. We included 937 patients with AMI, and divided those into the no-collateral group (n = 704) and the collateral group (n = 233) according to the presence or absence of collateral flow to the culprit lesion of AMI. The primary endpoint was the incidence of major adverse cardiac events (MACE), which was defined as a composite of all-cause death, non-fatal MI, re-admission for heart failure, and ischemia driven target vessel revascularization. The median follow-up duration was 473 days (Q1: 184 days- Q3: 1027 days), and a total of 263 MACE was observed during the study period. The incidence of MACE was significantly greater in the no-collateral group than in the collateral group (29.8% vs. 22.3%, p = 0.027). In the multivariate COX hazard model, the presence of collateral flow was inversely associated with MACE (HR 0.636, 95% CI 0.461-0.878, p = 0.006) after controlling multiple confounding factors. In conclusion, the presence of collateral flow to the culprit lesion of AMI was inversely associated with long-term adverse outcomes. Careful observation of collateral flow may be important in emergent coronary angiography to stratify a high-risk group among various patients with AMI.

Surgical repair of a posterior left ventricular aneurysm in a 4-year-old boy

Left ventricular aneurysms are rarely encountered in pediatric patients. A 4-year-old boy was diagnosed with severe mitral regurgitation and a posterior left ventricular aneurysm associated with a viral infection. The aneurysm was surgically resected and plicated longitudinally with a combination of an interrupted mattress and continuous over-and-over sutures with an outer felt reinforcement. The mitral regurgitation was reduced to a trivial degree postoperatively. The patient's postoperative recovery was good. He was discharged 31 days after surgery without cardiac dysfunction or lethal arrhythmia. Considering the location and spread of the aneurysm, an appropriate surgical procedure should be adopted for pediatric patients.

Factors associated with difficulty in crossing the culprit lesion of acute myocardial infarction

In percutaneous coronary intervention (PCI) to the culprit lesion of acute myocardial infarction (AMI), unsuccessful guidewire crossing causes immediate poor outcomes. It is important to determine the factors associated with unsuccessful guidewire crossing in AMI lesions. The purpose of this study was to find factors associated with difficulty in crossing the culprit lesion of AMI. We defined the difficult group when the guidewire used to cross the culprit lesion was a polymer jacket type guidewire or a stiff guidewire. We included 937 patients, and divided those into the non-difficult group (n = 876) and the difficult group (n = 61). Proximal reference diameter was significantly smaller in the difficult group than in the non-difficult group (p < 0.001), and degree of calcification was severer in the difficult group than in the non-difficult group (p < 0.001). In the multivariate stepwise logistic regression analysis, proximal reference diameter [odds ratio (OR) 0.313, 95% confidence interval (CI) 0.185–0.529, p < 0.001)], previous PCI (OR 3.065, 95% CI 1.612–5.830, p = 0.001), moderate-severe calcification (OR 4.322, 95% CI 2.354–7.935, p < 0.001), blunt type obstruction (OR 12.646, 95% CI 6.805–23.503, p < 0.001), and the presence of collateral to the culprit lesion (OR 2.110, 95% CI 1.145–3.888, p = 0.017) were significantly associated with difficulty in crossing the culprit lesion. In conclusion, previous PCI, calcification, blunt type obstruction, and the presence of collateral were associated with difficulty in crossing the culprit lesion, whereas proximal reference diameter was inversely associated with difficulty. Our study provides a reference to recognize the difficulty in crossing the culprit lesions of AMI for PCI operators, especially junior operators.

Chimney reconstruction provides a wider subaortic space and reduces the risk of pulmonary artery compression in the Norwood-type aortic arch reconstruction without patch supplementation

OBJECTIVES

Pulmonary artery (PA) compression by the neoaorta is a serious complication after the Norwood-type palliation (NP) for hypoplastic left heart syndrome. Either excess patch tailoring or limited use of autologous tissue may cause narrowing of the subaortic space. The chimney technique could theoretically provide a wide subaortic space.

METHODS

Twenty-nine patients with both pre- and post-NP computed tomography data available of the 37 consecutive patients who underwent NP in our institution were reviewed. Arch height, arch width, sinus of Valsalva diameter, area under the neoaortic arch and arch angle were measured. These patients were divided according to the neo-arch reconstruction technique, chimney reconstruction technique (CR) or conventional direct reconstruction technique (DR).

RESULTS

Median age and weight at NP were 2.1 months and 3.5 kg, respectively. Twenty-two patients underwent previous bilateral PA banding. During NP, 17 CR and 12 DR were performed. Four patients in the DR group developed PA compression. No neoaortic arch dilatation was found in either group. Post-NP arch width, area under the neo-arch and the arch angle were significantly larger in the CR group. Pre-NP arch height was significantly smaller in DR patients with PA compression than in those without.

CONCLUSIONS

The chimney technique decreased the risk of PA compression and provided a wider subaortic space and a less acute arch angle. This technique had no short-term effect on the neoaortic root. Small preoperative arch height is a potential risk factor for PA compression in DR, and the chimney technique could be an effective solution.

Clinical Factors Associated with Long Fluoroscopy Time in Percutaneous Coronary Interventions to the Culprit Lesion of Non-ST-Segment Elevation Myocardial Infarction

The clinical outcomes of patients with non-ST-segment elevation myocardial infarction (NSTEMI) were comparable or even worse than those with ST-segment elevation myocardial infarction (STEMI). Although successful percutaneous coronary intervention (PCI) to the culprit lesions of NSTEMI would improve the clinical outcomes, some PCI require long fluoroscopy time, reflecting the difficulty of PCI. This study aims to find clinical factors associated with long fluoroscopy time in PCI to the culprit lesion of NSTEMI. We included 374 patients and divided those into the conventional fluoroscopy time (n = 302) and long fluoroscopy time (n = 72) groups according to the quintiles of fluoroscopy time. Clinical and angiographic parameters were compared between the two groups. Calcification and tortuosity were significantly more severe in the long fluoroscopy time group than in the conventional fluoroscopy time group. The prevalence of previous coronary artery bypass grafting (CABG) and bifurcation lesions was significantly greater in the long fluoroscopy time group than in the conventional fluoroscopy time group. In the multivariate stepwise logistic regression analysis, previous CABG (odds ratio [OR], 3.368; 95% confidence interval [CI], 1.407-8.064; P = 0.006), bifurcation lesion (OR, 2.407; 95% CI, 1.285-4.506; P = 0.006), excessive tortuosity (versus mild to moderate tortuosity; OR, 4.095; 95% CI, 1.159-14.476; P = 0.029), and moderate to severe calcification (versus none to mild; OR, 5.792; 95% CI, 3.254-10.310; P < 0.001) were significantly associated with long fluoroscopy time. In conclusion, previous CABG, bifurcation, excessive tortuosity, and moderate to severe calcification were associated with long fluoroscopy time. Our study provided a reference for PCI operators to identify the difficulties in PCI to the culprit lesion of NSTEMI.

Comparison of half-turned truncal switch and conventional operations

 

OBJECTIVES

To compare conventional procedures with the half-turned truncal switch operation (HTTSO) for the management of complete transposition of the great arteries with left ventricular outflow tract (LVOT) obstruction using time-resolved 3-dimensional magnetic resonance phase-contrast imaging.

METHODS

We identified 2 cases that underwent the Rastelli procedure and one case that underwent the Réparation a l'étage ventriculaire before 2002 [conventional procedures group (group C)], and 16 cases of HTTSO that were performed between 2002 and 2020 [HTTSO group (group H)]. Postoperative haemodynamics were assessed using time-resolved 3-dimensional magnetic resonance phase-contrast imaging in cases in both groups.

RESULTS

The median follow-up period was 20.4 years in group C, and 6.1 years in group H. In group C, all 3 patients underwent reoperation because of postoperative right ventricular outflow tract obstruction and/or insufficiency. In addition, permanent pacemaker implantation was needed in 1 patient because of complete atrioventricular block complicated by ventricular septal defect enlargement. In group H, reoperation for LVOT/right ventricular outflow tract obstruction was not needed. A time-resolved 3-dimensional magnetic resonance phase-contrast imaging examination revealed high energy loss and wall shear stress in the winding LVOT in the group C. In contrast, low energy loss and wall shear stress, with straight and smooth LVOT, were identified in group H.

CONCLUSIONS

HTTSO was shown to be superior to conventional procedures because a straight and wide LVOT could be obtained. Therefore, HTTSO should be the first choice for complete transposition of the great arteries with LVOT obstruction.

Epigenetic Regulation of ALS and CMT: A Lesson from Drosophila Models

Amyotrophic lateral sclerosis (ALS) is the third most common neurodegenerative disorder and is sometimes associated with frontotemporal dementia. Charcot–Marie–Tooth disease (CMT) is one of the most commonly inherited peripheral neuropathies causing the slow progression of sensory and distal muscle defects. Of note, the severity and progression of CMT symptoms markedly vary. The phenotypic heterogeneity of ALS and CMT suggests the existence of modifiers that determine disease characteristics. Epigenetic regulation of biological functions via gene expression without alterations in the DNA sequence may be an important factor. The methylation of DNA, noncoding RNA, and post-translational modification of histones are the major epigenetic mechanisms. Currently, Drosophila is emerging as a useful ALS and CMT model. In this review, we summarize recent studies linking ALS and CMT to epigenetic regulation with a strong emphasis on approaches using Drosophila models.

Long-term results of large-calibre expanded polytetrafluoroethylene-valved conduits with bulging sinuses

OBJECTIVES

In Japan, homograft and bovine jugular vein are available in very limited institutions for the reconstruction of the right ventricular outflow tract, and handmade expanded polytetrafluoroethylene (ePTFE)-valved conduits have been widely used instead. This study aimed to clarify the long-term outcomes and the durability of the ePTFE-valved conduits purely by narrowing down to those with large sizes to eliminate the influence of the body growth.

METHODS

Between January 2002 and December 2015, patients who underwent right ventricular outflow tract reconstruction in 34 Japanese institutions using ePTFE-valved conduits with a diameter of ≥18 mm were included. All the valved conduits were made in the authors' institution and delivered to each participating institution.

RESULTS

Overall, 502 patients were included. Early mortality was 1.4% and not related to conduit failure. The overall survival rate was 98.2% at 5 years and 96.6% at 10 years. Freedom from conduit explantation was 99.5% at 5 years and 89.0% at 10 years. Three patients (0.13 per 100 patient-years) developed infective endocarditis of the conduit, and only 1 patient required conduit removal. Pulmonary insufficiency was mild or less in 480 (96%) patients, and conduit stenosis was mild or less in 436 (88%) patients at the latest follow-up.

CONCLUSIONS

By narrowing the analyses down to only ePTFE conduits with a large size, satisfactory long-term outcomes of these conduits with a fan-shaped valve and bulging sinuses were shown. These conduits would be among the optimal choices for right ventricular outflow tract reconstruction.

[Risk Analysis of Acute Kidney Injury after Cardiac Surgery and Protective Effect by Less Invasive Surgery]

OBJECTIVE

We aimed to determine the incidence and risk of acute kidney injury (AKI) in patients after cardiac surgery, and to assess the effects of less invasive cardiac surgery on the prevention of postoperative AKI.

METHODS

We retrospectively analyzed perioperative parameters in patients who underwent cardiac surgery. Risk factors for AKI were determined using univariate and multiple logistic regression models. The incidence of postoperative AKI was also compared between conventional and minimally invasive cardiac surgeries.

RESULTS

Among 126 patients, 36 (28.6%) who developed postoperative AKI stayed significantly longer in the intensive care unit(ICU), required prolonged postoperative ventilation and had a higher frequency of renal replacement therapy. Multivariate analysis revealed cardio-pulmonary bypass (CPB) duration and red blood cell transfusion as independent risk factors for postoperative AKI. The incidence of postoperative AKI was significantly lower after off-pump coronary artery bypass grafting than conventional coronary artery bypass grafting (CABG)(0% versus 11%, p=0.025), and after minimally invasive cardiac surgery compared with conventional valve surgery( 4% versus 44%, p=0.01) Conclusion:The duration of CPB and red blood cell transfusion were considered independent factors for the development of postoperative AKI. Less invasive cardiac surgeries might protect against postoperative AKI.

Association of the long fluoroscopy time with factors in contemporary primary percutaneous coronary interventions

BACKGROUND

Since the long fluoroscopy time in primary PCI for ST-segment elevation myocardial infarction (STEMI) could be an indicator of delayed reperfusion, it should be important to recognize which types of lesions require longer fluoroscopy-time in primary PCI. The purpose of this study was to investigate the association of the long fluoroscopy-time with clinical factors in primary percutaneous coronary interventions (PCI).

METHODS

A total of 539 patients who underwent primary PCI were divided into the conventional fluoroscopy-time group (Q1-Q4: n = 434) and the long fluoroscopy-time group (Q5: n = 105) according to the quintile of the total fluoroscopy time in primary PCI. Univariate and multivariate logistic regression analyses were performed to find associations between clinical variables and the long fluoroscopy-time.

RESULTS

In univariate logistic regression analysis, prevalence of diabetes mellitus, hemodialysis, and previous CABG were significantly associated with the long fluoroscopy-time. In addition, complex lesion characteristics such as lesion length, lesion angle, tortuosity, and calcification were associated with the long fluoroscopy-time. In multivariable logistic regression analysis, lesion length [per 10 mm incremental: odds ratio (OR) 1.751, 95% confidence interval (CI) 1.397-2.195, P<0.001], moderate-excessive tortuosity (vs. mild tortuosity: OR 4.006, 95% CI 1.498-10.715, P = 0.006), and moderate to severe calcification (vs. none-mild calcification: OR 1.865, 95% CI 1.107-3.140, P = 0.019) were significantly associated with the long fluoroscopy-time.

CONCLUSIONS

In primary PCI for STEMI, diffuse long lesion, tortuosity, and moderate-severe calcification were associated with the long fluoroscopy-time. These complex features require special attention to reduce reperfusion time in primary PCI.

The effect of a valved small conduit on systemic ventricle–pulmonary artery shunt in the Norwood-type palliation

OBJECTIVES

The aim of this study was to clarify the impact of valved systemic ventricle–pulmonary artery (SV–PA) shunt on outcomes after stage-1 Norwood-type palliation (NP) compared with the modified Blalock–Taussig shunt.

METHODS

Consecutive patients who underwent NP between 2003 and 2019 were enrolled. SV–PA shunts using the expanded polytetrafluoroethylene valved conduit were implanted in 18 patients (valved SV–PA group), and another 18 patients underwent modified Blalock–Taussig shunt during NP (modified Blalock–Taussig shunt group). All valved conduits were made in our institution in advance.

RESULTS

No differences in baseline characteristics were found between the groups, except for shunt size. During a median 2.9 (interquartile range 0.4–6.4, maximum 14.2) years of follow-up, 8 (22.2%) patients died across both groups. There were no statistically significant differences in early mortality (5.5% vs 11.1%, P = 0.55) and overall survival rates at 5 years (80.8% vs 71.4%, P = 0.48) in the valved SV–PA and modified Blalock–Taussig shunt groups. No statistically significant difference was observed in the frequency of interventions between the groups (31% vs 33%, P = 1.0). At the time of the bidirectional Glenn procedure, the systemic ventricular end-diastolic volume index was significantly lower (84 ± 24 vs 106 ± 31 ml/m2, P = 0.05) and the ejection fraction was significantly greater (62 ± 8% vs 55 ± 9%, P = 0.03) in the valved SV–PA group. There was no statistically significant difference in the pulmonary artery index (228 ± 85 vs 226 ± 60 mm2/m2, P = 0.92).

CONCLUSIONS

A valved SV–PA shunt using an expanded polytetrafluoroethylene valved conduit was associated with preserved ventricular function after NP and did not impair pulmonary artery growth by controlling pulmonary regurgitation.

Histopathologic Analysis of Explanted Polytetrafluoroethylene-Valved Pulmonary Conduits

The expanded polytetrafluoroethylene (ePTFE)-valved conduits as alternative material for right ventricular outflow reconstruction provides satisfactory long-term outcomes. The purpose of this study was to investigate degenerative changes in failed conduits through histopathologic analysis of the explanted specimens. All leaflets of explanted conduits were observed macroscopically, and their longitudinal sections were examined microscopically. Three typical findings, that is, calcification of the leaflet, neointimal proliferation, and proteinaceous infiltration into the leaflet, were evaluated quantitatively by measuring their degree and appearance probability. A total of 15 leaflets from 5 failed conduits (group F) and 12 leaflets from 5 nonfailed conduits (group non-F) were included. The median duration of implantation was 7.6 years (5.3-10.9 years) in group F and 1.3 years (0.7-3.9 years) in group non-F (P = 0.003). In group F, calcification tended to occur in the middle and upper third of the leaflet, causing stiffening, distortion, and exophytic concretion of the leaflet, and mean neointimal thickness on inflow and outflow surfaces were 0.33 ± 0.02 mm and 0.22 ± 0.01 mm, respectively. There was a moderately strong correlation between appearance probability of calcification in group F and that of proteinaceous infiltration in group non-F (correlation coefficient 0.67, P < 0.001). Proteinaceous infiltration into the leaflet was presumed be responsible for future calcification of the leaflet and subsequent stenotic conduit failure. Modification of the ePTFE material to prevent proteinaceous infiltration may contribute to improving the durability of ePTFE-valved conduit.

Early outcomes and computational fluid dynamic analyses of chimney reconstruction in the Norwood procedure†

OBJECTIVES

The ideal configuration of a reconstructed aortic arch in the Norwood procedure for hypoplastic left heart syndrome is still a matter of debate. Chimney reconstruction was developed to avoid postoperative complications and turbulent flow in the aortic arch. This study sought to clarify early outcomes of the procedure and verify its haemodynamic advantages using computational fluid dynamics (CFD).

METHODS

Fourteen consecutive patients with hypoplastic left heart syndrome or a variant who underwent chimney reconstruction in the Norwood procedure between January 2013 and March 2018 were enrolled. Median age and body weight at the time of operation were 2.5 months and 4.1 kg, respectively. Thirteen patients (93.9%) had been palliated with previous bilateral pulmonary artery (PA) banding. In addition, patient-specific CFD models of neoarches based on postoperative computed tomograms from 6 patients were created and the flow profiles analysed.

RESULTS

Survival rates at 1, 3 and 5 years were 76.6%, 67.3% and 67.3%, respectively. No patient developed left PA compression by neoaorta, neoaortic dilation or neoaortic insufficiency. Only 2 patients (14.3%) required surgical intervention for recoarctation. Fontan completion was performed on 5 patients. On CFD analysis, all reconstructed aortic arches showed low energy loss (9.16-14.4 mW/m2) and low wall shear stresses.

CONCLUSIONS

Chimney reconstruction was a feasible technique when homografts were not readily available. CFD analyses underscored the fact that this technique produced excellent flow profiles. Larger studies should be conducted to clarify long-term outcomes.